Ni50.8Ti49.2 alloy prepared by double-wire + arc additive manufacturing with a substrate heating temperature of 600 °C

Abstract

In this study, a Ni50.8Ti49.2 single-walled component was prepared in-situ using double-wire + arc additive manufacturing using a substrate heated to 600 °C and TA1 and ER-Ni wires used as raw materials. The microstructure and properties of the component were thoroughly investigated. The results revealed that Ni4Ti3 precipitated mainly in spherical and needle-like forms, contributing to improved component strength through coherent strain strengthening and lattice distortion, respectively. The maximum hardness value reached an impressive 531 HV0.2. DSC curves showed distinct transformation temperatures: As = −24.8 °C, Af = 11.7 °C, Ms = 12.5 °C, and Mf = −28.1 °C. The presence of the precipitated phase altered the Ni content of the matrix, leading to overlapping peaks during the phase transformation process. After 15 cycles of compression, the component exhibited an unrecoverable strain approaching 1.75 %, demonstrating a certain degree of superelasticity.